Question

A vitamin K shot is given to infants soon after birth. Nurses at Northbay Healthcare were involved in a study to see if how they handle the infants could reduce the pain the infants feel ("SOCR data nips," 2013). One of the measurements taken was how long, in seconds, the infant cried after being given the shot. A random sample was taken from the group that was given the shot using conventional methods (first table), and a random sample was taken from the group that was given the shot where the mother held the infant prior to and during the shot (second table).  

Crying Time of Infants Given Shots Using Conventional Methods

63	0	2	46	33	33
29	23	11	12	48	15
33	14	51	37	24	70
63	0	73	39	54	52
39	34	30	55	58	18

Crying Time of Infants Given Shots Using New Methods

0	32	20	23	14	19
60	59	64	64	72	50
44	14	10	58	19	41
17	5	36	73	19	46
9	43	73	27	25	18

You may assume the 2 sample t-procedures are safe to use. Call conventional 1 and new 2 in proceeding with analyses.

#10. Find the 95% confidence interval for the mean difference in mean crying time after being given a vitamin K shot between infants held using conventional methods and infants held by their mothers. Fill in blank 1 to report the bounds of the 95% CI. Enter your answers as lower bound,upper bound with no additional spaces and rounding bounds to three decimals.

Blank #1: 95% confident that the true mean difference in mean crying time after being given a vitamin K shot between infants using conventional methods and infants held by their mothers is between ____________and ___________________. In other words, the mean crying time of infants given vitamin K shot using conventional methods is anywhere from ______________ less than to _______________more than the mean crying time of infants given vitamin K shot using new methods.

#9. Is there enough evidence to show that infants cried less on average when they are held by their mothers than if held using conventional methods? Test at the 5% level.

Use the framework below to guide your work.

Hypotheses: :     Ho: mu1 = mu2; Ha: mu1 > mu2 (calling conventional 1 and new 2)   

Blank #2: Test statistic = _________ (round to two decimal places)

Blank #3:  p-value = __________ (round to four decimal places)

Blank #4: Test decision: We decide to ___________ Ho (reject or do not reject)

Blank #5: Conclusion back into the words of problem: The evidence __________(favors or does not favor) that the mean crying time of infants given vitamin K shot and being held by their mothers is less than the mean crying time of those who were given shot using conventional methods.

Answer 1

95% confident that the true mean difference in mean crying time after being given a vitamin K shot between infants using conventional methods and infants held by their mothers is between -13.077 and 9.077. In other words, the mean crying time of infants given vitamin K shot using conventional methods is anywhere from 13.077 less than to 9.077 more than the mean crying time of infants given vitamin K shot using new methods.



The evidence does not favour that the mean crying time of infants given vitamin K shot and being held by their mothers is less than the mean crying time of those who were given shot using conventional methods.